- The Gettysburg Battlefield is the area of the July 1–3, 1863, military engagements of the Battle of Gettysburg in and around Gettysburg, Pennsylvania. Locations of military engagements extend from the 4-acre (1.6 ha) site of the first shot at Knoxlyn Ridge on the west of the borough, to East Cavalry Field on the east. A military engagement prior to the battle was conducted at the Gettysburg Railroad trestle over Rock Creek, which was burned on June 27.
- Fluorine (Wikipedia)
Fluorine is a chemical element; it has symbol F and atomic number 9. It is the lightest halogen and exists at standard conditions as pale yellow diatomic gas. Fluorine is extremely reactive as it reacts with all other elements except for the light inert gases. It is highly toxic.